Those rules are for veterans who are NOT rated at 100%, and do not apply to your Dad. You need to file ASAP a VA form 21-4138 Statement in Support of Claim stating that your Dad and Mom now require the assistance of others for their day-to-day living. You do not have to complete the application process due to his rating and there is no financial test. He is entitled to an additional $654.00 (approximate) a month due to the 100%.
You should include a Physcian's Statement 21-2680 see this link for the form: http://www.veteranaid.org/docs/PhysicianStatementForA&A.pdf
Mention in the Statement in Support that you (he) believes that his is eligible for an increase in his compensation pay for Special Monthly Compensation as he now requires the attendance of another person with bathing, dressing etc.
I would also include in the packet a Statement of Occupancy from the facility they are in.
Highly recommend you mail this Return Receipt and to the proper Pension center for the state they reside in. You can find those addresses here on the forums or on the website.
This is really pretty great news for your Dad and Mom and hope this helps!